1. Field of the Invention
This invention relates to data reproduction, and more particularly, to rapid data reproduction using a plurality of optical beams to simultaneous play back a plurality of tracks on an optical disk.
2. Description of the Prior Art
In a conventional apparatus, rapid data reproduction is accomplished by playing back a plurality of tracks simultaneously using a plurality of optical beams. Conventional methods execute intentional track jumps as data is reproduced from an inner periphery to an outer periphery. However, data is missed during a track jump, thereby resulting in an incomplete reproduction of data. The track jump data-loss will now be explained in detail with reference to FIG. 3.
In FIG. 3, a track is spirally formed on a disk. Here, each turn of the track is represented by a solid line and labeled with a respective track number 1 through 12. Accordingly, the track begins at the top left of FIG. 3, and when a specific turn is completed, the right end is reached where the next track begins, as represented by the broken line. Actually, the reading beam moves in the radial direction of the disk while the disk rotates, thereby following the track. However, for purposes of illustration, FIG. 3 shows the reading action carried out by moving the reading beam relatively while the track is fixed. The bold lines of the track correspond to the portions of the track to be read by the reading beam.
Referring to FIG. 3, when three tracks are played back simultaneously from a position "a" on the track 4 using three beams, it is necessary to jump two tracks (i.e., three minus one tracks) from a position "b" in the direction of outer periphery after a single turn is completed to reproduce three new tracks.
Because the disk is rotating during the time required to perform the jump, the reading beam deflects in the forward direction to a position "c" of track 7, when the reading beam jumps two tracks in the direction of the outer periphery from position "b". Therefore, data from a position "e" to a position "c" on track 7 will not be read.
As described above, a conventional apparatus can rapidly reproduce data reproduction by playing back a plurality of tracks simultaneously using a plurality of optical beams irradiated on a disk. However, such an apparatus requires the optical beams to perform track jumps, thereby missing data. Thus, reproduction without missing data during a track jump remains an important problem to be solved.